Seismic noise assessment and network QC on single-station 3-component short-period Velocimeters

Seismic noise characterization and quality control are important components of seismic monitoring network management, particularly when three-component seismometers are used. This study presents a novel approach to achieving both objectives using the directional horizontal-to-vertical spectral ratio based on the Nakamura Technique. In this thesis, we present a comparative framework and a new method for evaluating the performance and reliability of three-component velocimeters. Our method uses DHVSR, a powerful tool that takes advantage of the recorded ground motion between the horizontal and vertical components of the seismometer to determine its health and performance, as well as to characterize the ambient noise wave field on site. We used field data to analyze the effectiveness of this method and deployed a Network of Seismic Stations based on the lessons learned from this research project. Furthermore, the proposed method not only provides valuable insights into the seismic noise characteristics of monitoring stations but also provides a robust quality control method for the 3-component seismometers used in the network. In addition, this new approach improves the overall performance of a seismic network by facilitating real-time monitoring and a rapid response to changes in noise conditions. Our findings demonstrate significant improvements in the reliability and efficiency of seismic data collection and analysis. In conclusion, our study presents a quantitative approach for rapid and automatic seismic noise characterization and network quality control, specifically designed for the long-term deployment of short-period three-component seismometers.